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Experimental investigation on a high subsonic compressor cascade flow

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Chinese Journal of Aeronautics 2015年第4期28卷 1034-1043页

作者： Zhang Haideng Wu Yun Li Yinghong LU Huawei College of Aeronatutics and Aerospace Airforce Engineering University School of Energy and Power Beihang University Marine Engineering College Dalian Marinetime University

With the aim of deepening the understanding of high-speed compressor cascade flow,this paper reports an experimental study on NACA-65 K48 compressor cascade with high subsonic inlet flow.With the increase of passage pressurizing ability, endwall boundary layer behavior is deteriorated, and the transition zone is extended from suction surface to the endwall as the adverse pressure gradient increases.Cross flow from endwall to midspan, mixing of corner boundary layer and the main stream, and reversal flow on the suction surface are caused by corner separation vortex structures.Passage vortex is the main corner separation vortex.During its movement downstream, the size grows bigger while the rotating direction changes, forming a limiting circle.With higher incidence, corner separation is further deteriorated, leading to higher flow loss.Meanwhile, corner separation structure, flow mixing characteristics and flow loss distribution vary a lot with the change of incidence.Compared with low aspect-ratio model, corner separation of high aspect-ratio model moves away from the endwall and is more sufficiently developed downstream the cascade.Results obtained present details of high-speed compressor cascade flow,which is rare in the relating research fields and is beneficial to mechanism analysis, aerodynamic optimization and flow control design.

关键词： Compressor Corner separation High speed Secondary flow Transition

Effect of tip geometry and tip clearance on aerodynamic performance of a linear compressor cascade

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Chinese Journal of Aeronautics 2013年第3期26卷 583-593页

作者： Zhong Jingjun Han Shaobing LU Huawei Kan Xiaoxu Marine Engineering College Dalian Maritime University

The tip leakage flow between a blade and a casing wall has a strong impact on compressor pressure rise capability, efficiency, and stability. Consequently, there is a strong motivation to look for means to minimize its impact on performance. This paper presents the potential of passive tip leakage flow control to increase the aerodynamic performance of highly loaded compressor blades. Experimental investigations on a linear compressor cascade equipped with blade winglets mounted to the blade tips have been carried out. Results for a variation of the tip clearance and the winglet geometry are presented. Current results indicate that the use of proper tip winglets in a compressor cascade can positively affect the local aerodynamic field by weakening the tip leakage vortex. Results also show that the suction-side winglets are aerodynamically superior to the pressure-side or combined winglets. The suction-side winglets are capable of reducing the exit total pressure loss associated with the tip leakage flow and the passage secondary flow to a significant degree.

关键词： Compressor cascade Experimental investigation Tip clearance Tip geometry Tip leakage vortex

HTDet:A Clustering Method Using Information Entropy for Hardware Trojan Detection

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Tsinghua Science and Technology 2021年第1期26卷 48-61页

作者： Renjie lu Haihua Shen Zhihua Feng huawei Li Wei Zhao Xiaowei Li the University of Chinese Academy of Sciences Beijing 101408China Beijing Institute of Computer Technology and Application Beijing 100854China the State Key Laboratory of Computer Architecture Institute of Computing TechnologyChinese Academy of SciencesBeijing 100190China

Hardware Trojans(HTs)have drawn increasing attention in both academia and industry because of their significant potential threat.In this paper,we propose HTDet,a novel HT detection method using information entropybased clustering.To maintain high concealment,HTs are usually inserted in the regions with low controllability and low observability,which will result in that Trojan logics have extremely low transitions during the simulation.This implies that the regions with the low transitions will provide much more abundant and more important information for HT detection.The HTDet applies information theory technology and a density-based clustering algorithm called Density-Based Spatial Clustering of Applications with Noise(DBSCAN)to detect all suspicious Trojan logics in the circuit under detection.The DBSCAN is an unsupervised learning algorithm,that can improve the applicability of HTDet.In addition,we develop a heuristic test pattern generation method using mutual information to increase the transitions of suspicious Trojan logics.Experiments on circuit benchmarks demonstrate the effectiveness of HTDet.

关键词： Hardware Trojan(HT)detection information entropy Density-Based Spatial Clustering of Applications with Noise(DBSCAN) unsupervised learning clustering mutual information test patterns generation

Performance Analysis of Inter-Stage Leakage Flows at Rotating Conditions in an Axial Compressor

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Journal of Thermal Science 2020年第6期29卷 1558-1568页

作者： KONG Xiaozhi LIU Yuxin LU Huawei TIAN Zhitao XIN Jianchi Naval Architecture and Ocean Engineering College Dalian Maritime UniversityDalian 116026China Marine Engineering College Dalian Maritime UniversityDalian 116026China

For the compressor with shrouded stator blades,the stator well is a rotor-stator space between the rotating drum and the stationary shroud.Due to the pressure difference,a reverse leakage flow would travel through the stator well and inject into the main flow path.Although,the labyrinth seal is commonly placed under the shroud,the rotation effect and seal clearance variation in actual operation process have great impact on the characteristics of this inter-stage leakage,as well as the compressor performance.In this paper,experiments were conducted at a compressor inter-stage seal test rig.The leakage flow rates,total temperatures and swirl ratios were obtained at different speeds and working clearances.The proportions of rotation effect and the clearance reduction effect were analyzed by data processing.Comparisons indicate that the working clearance and leakage flow reduce about 43%and 50%respectively,when the rotational speedω=8100 r/min.The proportion of reduction caused by the rotation effect is around 15%,while the influence of working clearance variation is much greater,accounting for about 35%.The windage heating coefficient and swirl ratio in the outlet cavity are almost in exponential relationship with the rotor speed.The increases in total temperature and swirl ratio generated by the rotation effect are found to be about 80%.In addition,the swirl and radial velocity profiles in the cavities were discussed by validated numerical simulations to reveal the typical flow characteristics.The data presented can provide guidance for better leakage conditions prediction as well as the inter-stage seal design enhancement.

关键词： shrouded stator blade inter-stage seal rotor-stator cavity leakage flow windage heating swirl ratio

Effectiveness and safety of Ginkgo biloba extract(GBE50)in the treatment of dizziness caused by cerebral arteriosclerosis:a multi-center,double-blind,randomized controlled trial

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Journal of Traditional Chinese Medicine 2022年第1期42卷 83-89页

作者： SHA Rina TANG lu DU Yawei WU Shengxian SHI huawei ZOU Hongxin ZHANG Xuran DONG Xinglu ZHOU Li the First clinical medical college Beijing University of Chinese MedicineBeijing 100029China Department of Neurology Dongzhimen HospitalBeijing University of Chinese MedicineBeijing 100700China

OBJECTIVE:To evaluate the effectiveness and safety of Ginkgo biloba extract(GBE50)in the treatment of dizziness caused by cerebral arteriosclerosis.METHODS:This was a multi-center,double-blind,double-dummy,positive-controlled,parallel randomized controlled clinical trial with 1∶1 allocation.We recruited 404 patients with dizziness caused by cerebral arteriosclerosis(blood stasis symptom pattern)in 10 hospitals in China.GBE50 group received GBE50 and Naoxinqing tablet(NXQ)of mimetic agent,control group received NXQ and GBE50 of mimetic agent.The main outcome was Traditional Chinese Medicine(TCM)symptom pattern score of blood stasis after 6 weeks.The secondary outcomes were changes in the dizziness handicap inventory(DHI)score,vertigo visual analogue scale(VAS)score,the university of California vertigo questionnaire(UCLA-DQ)score and single-item symptom score of TCM from baseline to 2,4 and 6 weeks.Safety indicators included the incidence of adverse events,severe adverse events and laboratory examination including blood routine,liver function,renal function,and so forth.RESULTS:The total effective rate of TCM symptom pattern score in the GBE50 group after 6 weeks of treatment was higher than that in the control group,the difference in rate was statistically significant(92.67%vs 83.07%,P=0.004).Compared with the control group,there was no difference in the incidence of adverse reactions(9.95%vs 14.85%,P=0.136).CONCluSION:The treatment of dizziness caused by cerebral arteriosclerosis with GBE50 is effective,safe and reliable.

关键词： Ginkgo biloba intracranial arteriosclerosis dizziness treatment outcome randomized controlled trial

Cryptochrome 1 Inhibits Shoot Branching by Repressing the Self-Activated Transciption Loop of PIF4 in Arabidopsis

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Plant Communications 2020年第3期1卷 98-106页

作者： huawei Zhai lu Xiong Hongyu Li Xiangguang Lyu Guodong Yang Tao Zhao Jun Liu Bin Liu The National Key Facility for Crop Gene Resources and Genetic Improvement(NFCRI) Institute of Crop ScienceChinese Academy of Agricultural SciencesBeijingP.R.China State Key Laboratory of Crop Biology College of Life SciencesShandong Agricultural UniversityTaianShandongP.R.China

Cryptochrome 1(CRY1)is an important light receptor essential for de-etiolation of Arabidopsis seedlings.However,its function in regulating plant architecture remains unclear.Here,we show that mutation in CRY1 resulted in increased branching of Arabidopsis plants.To investigate the underlying mechanism,we analyzed the expression profiles of branching-related genes and found that the mRNA levels of Phytochrome Interaction Factor 4(PIF4)and PIF5 are significantly increased in the cry1 mutant.Genetic analysis showed that the pif4 or pif4pif5 mutant is epistatic to the cry1 mutant,and overexpression of PIF4 conferred increased branching.Moreover,we demonstrated that PIF4 proteins physically associate with the G-box motif within the PIF4 promoter to form a self-activated transcriptional feedback loop,while CRY1 represses this process in response to blue light.Taken together,this study suggests that the CRY1–PIF4 module regulates gene expression via forming a regulatory loop and shoot branching in response to ambient light conditions.

关键词： cryptochrome PIF branching basic helix-loop-helix photoreceptor Arabidopsis

Effect of Winglet Geometry Arrangement and Incidence on Tip Clearance Control in a Compressor Cascade

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Journal of Thermal Science 2014年第4期23卷 381-390页

作者： HAN Shaobing ZHONG Jingjun LU Huawei KAN Xiaoxu YANG Ling Marine Engineering College Dalian Maritime University

An experimental study is conducted to investigate the influences of blade tip winglet on the flow field of a compressor cascade. The tests are performed in a low speed linear cascade with stationary endwall, with three blade tip configurations, including the baseline tip, the suction-side winglet tip and the pressure-side winglet tip. The flowfield downstream of the cascade is measured using five-hole probe, from which the three-dimensional velocity field, vorticity field and pressure field are obtained. Static pressure measurements are made on the endwall above the blade row using pressure taps embedded in the plywood endwall. All measurements are made at both design and off-design conditions for tip clearance level of about 2 percent of the blade chord. The results revealed the incidence variation significantly affects the secondary flow and the associated loss field downstream of the cascade, where the tip leakage vortex and passage vortex exist as the major contributors on the field. The winglet geometry arrangements can change the trajectory of the tip leakage vortex. The suction-side winglet tip blade provides a lower overall total pressure loss coefficient when compared to the baseline tip blade and pressure-side winglet tip blade at all incidence angles.

关键词：叶尖泄漏涡压气机叶栅几何布置发病率间隙控制翼梢小翼压力损失系数非设计条件

卡式微柱凝胶试验联合盐水法在输血检验中的应用价值

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智慧健康 2023年第13期9卷 85-88页

作者：卢华玮苏州工业园区星海医院检验科江苏苏州215101

目的探讨卡式微柱凝胶试验联合传统盐水法在输血检验中的应用价值。方法选取2019年4月-2022年7月本院收治的82例输血检验患者为此次调查对象,随机分成常规组和研究组,输血检验方法分别以盐水法、卡式微柱凝胶联合盐水法为主,分析两组... 详细信息

目的探讨卡式微柱凝胶试验联合传统盐水法在输血检验中的应用价值。方法选取2019年4月-2022年7月本院收治的82例输血检验患者为此次调查对象,随机分成常规组和研究组,输血检验方法分别以盐水法、卡式微柱凝胶联合盐水法为主,分析两组检验价值。结果通过本次研究数据可知,研究组正向定型及反向定型符合率更高(P<0.05);研究组输血时不良反应概率更低(P<0.05);研究组输血检验满意度更高(P<0.05);研究组检验时间长于常规组(P<0.05)。结论卡式微柱凝胶联合盐水法在输血治疗患者中有重要临床价值,虽然检验时间较长,但是患者满意度很高,准确率高,还有效降低输血时的不良反应,值得推广。

关键词：输血检验满意度盐水法卡式微柱凝胶

Tunable and efficient microwave absorption from mesophase pitch carbide with designable electromagnetic properties

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Defence Technology（防务技术） 2023年第10期28卷 222-235页

作者： Junyu lu Haoruo Zhang Yang Chen Mushan Yuan Mei Liang Zhengguang Heng huawei Zou The State Key Lab of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu 610065China School of New Energy and Materials Engineering Southwest Petroleum UniversityChengdu 610500China

In order to obtain the microwave absorption(MA)materials with light weight,high efficiency and tunable properties,the carbonized mesophase pitch(CMP)with the variation in carbonization temperatures and particle sizes were prepared and characterized.The carbonization temperature mainly controlled the graphitization degree of the CMP to affect their conductive loss.The carbon residues were generated on the CMP surface when the temperature was higher than 700℃,which contributed significantly to the polarization loss of the CMP.For scale regulation,the segregation between the particles in the paraffin ring caused by the reduction particles of CMP carbonization at 750℃(750 CMP)resulted in a significant reduction in conductive losses while improving their impedance matching.The 750 CMP over 300 mesh sieved had the strongest MA properties of-53 d B at 3.4 GHz within 5.5 mm.Moreover,the prepared CMPs were multi-layer compounded and optimized by CST microwave studio.The synergistic effect derived from the improved impedance matching and the enhanced interfacial polarization resulted in significant reflection loss in multi-layer CMP.Overall,these findings lead to the systematically regulation of carbon-based materials for MA,showing an attractive application prospect for the preparation of high-performance MA materials.

关键词： Microwave absorption Mesophase pitch Broadband Dielectric loss Interfacial polarization